A very good overview of hydroformylation is found in Adv. Organometallic Chemistry 17 (1979) "Hydroformylation", by Pruett. The reaction mechanism is discussed as well as substrates, products and by-products, catalysts other than cobalt and rhodium, etc.
N-vinyl-2-pyrrolidinone is a commercially available intermediate compound usually formed by the reaction of 2-pyrrolidinone and acetylene. It is useful as a monomer for various copolymerizations. It does not appear the concept of hydroformylating N-vinyl-2-pyrrolidinone to produce isomeric products has been accomplished using low pressures.
In Journal of Orangometallic Chemistry, 268 (1984) 167-174, the hydrocarbonylation and hydroformylation of .beta.-substituted N-vinylphthalimides catalyzed by Rh or Pd catalysts has been reported. N-protected aminoacid derivatives were prepared. The reaction is strongly affected by the nature of the substitutents. The required substrates were prepared by a relatively complex scheme involving alkylation of phthalamide and Ru-catalyzed isomerization.
In J. Org. Chem. 1980, 45, 2145-2151, Stille discusses the asymmetric hydroformylation and hydroxycarboxylation of enamides. Here it was stated that previously rhodium-catalyzed asymmetric hydroformylation has been confined to simple olefins and it was found that much higher optical yields were obtained with rhodium catalyzed asymmetric hydrogenation of vinyl amides as opposed to the use of simple olefins. In this study, enamides included N-vinylsuccinimide, N-vinylphthalamide, N-acyl-2-pyrrolines, N-vinylacetamide, N-allylacetamide. The structures of these compounds affected the reaction rate and selectivity. It was reported that trisubstituted enamides, N-(2-methylpropenyl)acetamide and N-(2-methylpropenyl) phthalimide were completely unreactive and linear disubstituted enamides reacted sluggishly in comparison with cyclic enamides. The reaction of N-vinyl-pyrrolidinone, a cyclic monoamido olefin, was not included.
The hydroformylation of N-acylated aminoolefins is demonstrated in J. Falbe, "New Synthesis with Carbon Monoxide", Springer-Verlag, Berlin, Heidelberg, New York, 1980. At page 129 data shows the hydroformylation of N-vinylpyrrolidone using Rh.sub.2 O.sub.3 +phenothiazine as a catalyst. However, here the pressure used is 700 bars or approximately 10,150 psig.
The comparison of Rh and Co catalyst on product selectivities (linear vs. branched products) was also revealed in Falbe, "New Synthesis With Carbon Monoxide", P. 128.
Starting from N-vinylphthalimide, a 78% yield of the 3-phthalimidopropanaldehyde and 2-phthalimidopropanaldehyde in a ratio of 2.5:1 was obtained. The Rh-related catalyst afforded a relatively reverse selectivity.
A study reported by Jardine in Polyhedron, No. 7-8, 569-605, 1982 provides insight into a comparison of carbonylhydrido tris(triphenylphosphine)rhodium(I), RhH(CO)(PPh.sub.3).sub.3 as a hydroformylation catalyst compared with other reactions and concludes that, though RhH(CO)(PPh.sub.3).sub.3 is the best hydroformylation catalyst, it is disappointing in other reactions. For instance, chlorotris(triphenylphosphine)rhodium(I) is probably a more generally useful hydrogenation catalyst and dichloro tris(triphenylphosphine)ruthenium(II) is probably a more effective isotope exchange catalyst.
Brown discusses reactivity and selectivity in catalysis by rhodium complexes in "Metals in Organic Synthesis" in Chemistry and Industry, 2 Oct. 1982. It was concluded that organorhodium complexes are uniquely effective in catalysis involving a series of linked intermediates where hydrogen, an olefin and possibly carbon monoxide are simultaneously coordinated and undergo intracomplex rearrangements. This article also discussed work involving asymmetric homogeneous hydrogenation where effective catalysts are chiral chelating biphosphines possessing a relatively rigid backbone and are asymmetric either at phosphorous or in the interphosphine chain. Further, a model for the mechanism of asymmetric hydrogenation is discussed. Vinyl acetates are mentioned as providing "good optical yields". Brown asserts there is much potential in organic synthesis for a reaction which effects catalytic conversion of terminal or other .alpha.-olefins into homologous aldehydes with high and controllable regioselectivity. The selectivity is thought to be dependent on reaction variables and concentration of free triphenylphosphine.
In an article entitled "Synthesis of Intermediates by Rhodium-Catalyzed Hydroformylation" in Angew. Chem. Ind. Ed. Engl. 19, 178-183 (1980), Himmele et al. discuss asymmetric hydroformylations in the presence of chiral phosphanes, but state that the enantiometric purity of the products is not high enough for industrial-scale synthesis (For example 20-30%).
These references do not appear to discuss the synthesis of amino-propanaldehydes, diaminopropanes and hydroxyaminopropanes by the reaction of commercially available N-vinyl-2-pyrrolidinone with syngas in the presence of a rhodium-containing compound at a low pressure with or without additional phosphine ligand and mild temperature and the subsequent reductive amination of the aldehydes to the final products. Diaminopropanes can be used in medicinals, dyes, rubber accelerators and analytical reagents. Diaminopropanes such as 1,2-diaminopropane can also be used in the production of epoxy resins. The final product distribution is controlled by regioselectivity of N-vinyl-2-pyrrolidinone hydroformylation.